Limits...
Decreasing risk of hepatitis A infection in León, Nicaragua: evidence from cross-sectional and longitudinal seroepidemiology studies.

Mayorga Perez O, Brinkhof MW, Egger M, Frösner G, Herzog C, Zwahlen M - PLoS ONE (2014)

Bottom Line: The proportion of seropositive children aged 1.5 to 6 years was 42% in 2003 compared to 67% in 1995/96.The age-specific geometric mean of the quantified anti-HAV antibody levels assessed in 2003 was highest at age 4 and decreased steadily up to age 40.The decreasing age-specific GMC of anti-HAV antibodies during adulthood in a country with endemic HAV indirectly suggests that ongoing HAV exposure in the community has marginal boosting effect on antibody levels once protective immunity has been established by natural infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Parasitology, Faculty of Medical Sciences, National Autonomous University, León, Nicaragua.

ABSTRACT

Background and objectives: Nicaragua is highly endemic for hepatitis A. We aimed to provide an estimate of the change in the age-specific risk of hepatitis A virus (HAV) infection based on serological data from cross-sectional and longitudinal samples collected in León, Nicaragua, in 1995/96 (n = 979) and 2003 (n = 494).

Methods: The observed age-specific prevalence of anti-HAV antibodies was correlated to the age-specific risk of infection by calculating the probability of freedom from infection at a specific age.

Results: The proportion of seropositive children aged 1.5 to 6 years was 42% in 2003 compared to 67% in 1995/96. Estimated annual risk of infection for a 3-year old child was 30% (95% CI: 27.0%, 33.1%) in 1995 and 15.5% (95% CI: 12.4%, 19.0%) in 2003. There was good agreement between estimates based on cross-sectional and longitudinal data. The age-specific geometric mean of the quantified anti-HAV antibody levels assessed in 2003 was highest at age 4 and decreased steadily up to age 40.

Conclusions: The substantially lower risk of HAV infection in 2003 than in 1995 for young children indicates a beginning transition from high to intermediate endemicity in León, Nicaragua. Consecutive age-stratified serosurveys are useful to assess changes in risk of infection following public health interventions. The decreasing age-specific GMC of anti-HAV antibodies during adulthood in a country with endemic HAV indirectly suggests that ongoing HAV exposure in the community has marginal boosting effect on antibody levels once protective immunity has been established by natural infection.

Show MeSH

Related in: MedlinePlus

Estimated age-specific risk (95% confidence intervals) of HAV infection in 1995 from cross-sectional and longitudinal samples.The solid circles represent estimates derived from the cross-sectional 1995 survey and open circles the estimates from the longitudinal data.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3921130&req=5

pone-0087643-g002: Estimated age-specific risk (95% confidence intervals) of HAV infection in 1995 from cross-sectional and longitudinal samples.The solid circles represent estimates derived from the cross-sectional 1995 survey and open circles the estimates from the longitudinal data.

Mentions: Analysis of the longitudinal data obtained from the placebo group of the 1995 study showed an annual 25% (95% CI 14% to 46%) risk of infection for a 3-year old child (Figure 2). There was good agreement between the estimated annual risk of infection from the longitudinal and cross-sectional studies in the 1995/96 samples, with the exception of 4-year old children in whom the longitudinal data indicated a lower risk of infection compared with that calculated from the cross-sectional sample (Figure 2).


Decreasing risk of hepatitis A infection in León, Nicaragua: evidence from cross-sectional and longitudinal seroepidemiology studies.

Mayorga Perez O, Brinkhof MW, Egger M, Frösner G, Herzog C, Zwahlen M - PLoS ONE (2014)

Estimated age-specific risk (95% confidence intervals) of HAV infection in 1995 from cross-sectional and longitudinal samples.The solid circles represent estimates derived from the cross-sectional 1995 survey and open circles the estimates from the longitudinal data.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921130&req=5

pone-0087643-g002: Estimated age-specific risk (95% confidence intervals) of HAV infection in 1995 from cross-sectional and longitudinal samples.The solid circles represent estimates derived from the cross-sectional 1995 survey and open circles the estimates from the longitudinal data.
Mentions: Analysis of the longitudinal data obtained from the placebo group of the 1995 study showed an annual 25% (95% CI 14% to 46%) risk of infection for a 3-year old child (Figure 2). There was good agreement between the estimated annual risk of infection from the longitudinal and cross-sectional studies in the 1995/96 samples, with the exception of 4-year old children in whom the longitudinal data indicated a lower risk of infection compared with that calculated from the cross-sectional sample (Figure 2).

Bottom Line: The proportion of seropositive children aged 1.5 to 6 years was 42% in 2003 compared to 67% in 1995/96.The age-specific geometric mean of the quantified anti-HAV antibody levels assessed in 2003 was highest at age 4 and decreased steadily up to age 40.The decreasing age-specific GMC of anti-HAV antibodies during adulthood in a country with endemic HAV indirectly suggests that ongoing HAV exposure in the community has marginal boosting effect on antibody levels once protective immunity has been established by natural infection.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Parasitology, Faculty of Medical Sciences, National Autonomous University, León, Nicaragua.

ABSTRACT

Background and objectives: Nicaragua is highly endemic for hepatitis A. We aimed to provide an estimate of the change in the age-specific risk of hepatitis A virus (HAV) infection based on serological data from cross-sectional and longitudinal samples collected in León, Nicaragua, in 1995/96 (n = 979) and 2003 (n = 494).

Methods: The observed age-specific prevalence of anti-HAV antibodies was correlated to the age-specific risk of infection by calculating the probability of freedom from infection at a specific age.

Results: The proportion of seropositive children aged 1.5 to 6 years was 42% in 2003 compared to 67% in 1995/96. Estimated annual risk of infection for a 3-year old child was 30% (95% CI: 27.0%, 33.1%) in 1995 and 15.5% (95% CI: 12.4%, 19.0%) in 2003. There was good agreement between estimates based on cross-sectional and longitudinal data. The age-specific geometric mean of the quantified anti-HAV antibody levels assessed in 2003 was highest at age 4 and decreased steadily up to age 40.

Conclusions: The substantially lower risk of HAV infection in 2003 than in 1995 for young children indicates a beginning transition from high to intermediate endemicity in León, Nicaragua. Consecutive age-stratified serosurveys are useful to assess changes in risk of infection following public health interventions. The decreasing age-specific GMC of anti-HAV antibodies during adulthood in a country with endemic HAV indirectly suggests that ongoing HAV exposure in the community has marginal boosting effect on antibody levels once protective immunity has been established by natural infection.

Show MeSH
Related in: MedlinePlus